Several attempts have been made to provide a sealable cover for an open beverage container. The best of these have a pivoted spout through which the contents of the container can be withdrawn. Movement of the spout through a sector of around ninety degrees or less, controls a valve in the withdrawal passage to open or shut off the flow. Venting the interior of the container is also opened or closed as a function of the position of the spout. As a practical matter, these devices must be capable of being molded of standard plastic materials, and with a minimum number of parts, and also with a simple assembly procedure.
These devices have gone through a significant evolution in design, an earlier form of the device being shown in U.S. Pat. No. 5,065,909. These devices have shown that there are a couple of persistent problems associated with previous designs. One is the necessity to open the vent before the valve in the withdrawal passage is opened, in order to release the gas pressure from carbonated beverages before it can squirt out liquid through the spout, to the consternation of anyone in the immediate vicinity. The other problem is the maintenance of an adequate seal at all points along paths leading from the interior of the container to the exterior of the device in order to prevent leakage when the unit is fully closed. One of the promising forms of the device provides a vent opening in the top surface of the cover at a point remote from the pivoted valve. In the closed position of the valve, a plug on the spout enters the vent opening, and supposedly closes it. A ball-ended plug can provide a snap-in feature retaining the closed position of the spout. Experience with this construction has established that forcing the ball into the vent opening, and then on through it, tends eventually to enlarge the opening to the point that a full seal is lost The material of the cover does not fully contract back onto the plug after the maximum diameter of the ball end passes beyond the seal point.
Maintenance of a seal has also been a problem at the journals and bearings associated with the pivoted valve. If the bearings provide a possible passage into the container, closing them off without excessive and complicated arrangements has proven to be difficult. The use of domeshaped journals and bearings to avoid apertures in the walls of the valve receptacle seemed to be a good idea, but did not provide a positive location for either the valve axis or the vent plug. The present invention appears to provide a solution to these problems.